Ok Gang...I've got a for sure way to diagnose torque converter lock up issues where it lock and unlocks at about 45-50 MPH. I had a gent call me yesterday with this problem and he's replace both batteries, alternator and the APPS sensor. Attempted all the different wiring issues (adding ground, tinfoil etc.) nothing worked. Like I told him the truck ran 11 years without all this stuff and doesn't require any wiring change to make it work. What it needs is the damaged part to be replaced. So he's returned the wiring back to stock setup.Now I told him to unhook the alternator fuse and take it for a ride... Guess what... No problems! Even though he replaced the alternator it has a damaged diode in it and it bleeding AC noise into the electrical system.So before doing any wiring mods, tinfoil, adding grounds, adding filter... PLEASE! Bench test your alternator! This is the second time I've suggested this and both time resolved the torque converter lock up issue.

I have fixed two trucks. Both had <.1 volts AC. On my truck,I disconnected polished and reconnected every ground and foil wrapped the ground over the alternator and relocated it. The other truck had very loose ground cables at the batterys. That truck I also did the foil wrap procedure because it was the cure of the day. Both trucks are doing fine 6 months later. Not always an alternator problem. Remember the basics

I have fixed two trucks. Both had <.1 volts AC. On my truck,I disconnected polished and reconnected every ground and foil wrapped the ground over the alternator and relocated it. The other truck had very loose ground cables at the batterys. That truck I also did the foil wrap procedure because it was the cure of the day. Both trucks are doing fine 6 months later. Not always an alternator problem. Remember the basics

True, lots of different things can cause TCL issues, bad grounds, bad electrical connections and bad battries being just a few. However, when TCL Issues are being caused by a severely damaged alternator (above .1 VAC), you can clean all the grounds, electrical connetions and tin foil all the wires you want to, but it won't cure the problem. Beeen there done that, Mopar1973Man was right about this one. HAPPY NEW YEAR!!!

True, lots of different things can cause TCL issues, bad grounds, bad electrical connections and bad battries being just a few. However, when TCL Issues are being caused by a severely damaged alternator (above .1 VAC), you can clean all the grounds, electrical connetions and tin foil all the wires you want to, but it won't cure the problem. Beeen there done that, Mopar1973Man was right about this one. HAPPY NEW YEAR!!!

Since I put the battery shims in and tightened the cables and cleaned the pcm ground I have not had any issues. my alt is still putting out around 30 VAC. I can hear the bearings are getting a little growly so it may have to be replaced this year. 275,000 miles and it is still the original alternator.

my alt is still putting out around 30 VAC.

I would get that alternator changed soon... Nothing in the vehicle is designed for 30 Volts AC or even 30 volts DC... You asking to do damage to the electronics of the truck. The only thing that keeping in some check is the batteries. But I highly suggest you get that replaced ASAP!

I would get that alternator changed soon... Nothing in the vehicle is designed for 30 Volts AC or even 30 volts DC... You asking to do damage to the electronics of the truck. The only thing that keeping in some check is the batteries. But I highly suggest you get that replaced ASAP!

I'm going to check it again tomorrow just to see. Refresh my memory; how do I check it with the voltmeter? Thanks!

Bad diodes that will cause the 30vac also will sometimes cause the alternator to howl that to some folks sounds like bearings

Bad diodes that will cause the 30vac also will sometimes cause the alternator to howl that to some folks sounds like bearings

Well guess what?!?!? I tested it just now and it throws 31.4 VAC. Then when I get that bearing sound it goes down to 27.5 VAC or so. Interesting.... I'll have to start looking for a new alternator I guess. VDC it is at 14.5 or so. However I didn't check to see what it was when it makes the noise.

How can a diode make a noise? The alternator is made up of a stator (3 seperate windings) 6 diodes( 1+ & 1- for each stator winding) & the rotor winding that spins and controls output (control depends on amperage sent to the rotor by the regulator) OK, one winding has poor or no output (winding failure or bad diode) Think of it as a 3 cylinder engine. 2 cyl firing & 1 not firing, Will it shake? Yes That is what makes the noise (imbalance of power)

It is definitely not working like it should. There is a shop that has a 160 amp for 145.00. 1 year warranty and they will throw it on the bench to show me there are no VAC coming from it. Should I keep looking for a 180 or is 160 good enough?Thanks!Sent from my torqued out reuterbender

Hello Guys,Yesterday on the way to work it was hunting in and out of 4th etc. On the way home all is well. This morning, hunting in and out of 4 so I kicked it out of OD and its hunting in and out 3 and lock or second, who knows. I brought my multimeter this am and tested my AC while it was running before I shut it of. It was at .05. When I tested it yesterday it was at .02 to .04. My Scangauge picked up a 1682 code. (My first one ever)I'm not sure from yesterday or this am. I'm thinking my alternator is just done. Thoughts??

Well guess what?!?!? I tested it just now and it throws 31.4 VAC. Then when I get that bearing sound it goes down to 27.5 VAC or so. Interesting.... I'll have to start looking for a new alternator I guess. VDC it is at 14.5 or so. However I didn't check to see what it was when it makes the noise.

I would STRONGLY recommend not to run the truck again until the alternator is fixed... Or at least only run it on batteries. 20VAC spikes WILL kill your ECM, PCM, VP44 controller and just about every computer on the truck... including your chip. You are looking at potentially $3000 of fixes here that won't pop up immediately... They will lurk and burn out slowly. I know because i've been down that road. Don't look for an alternator, go get one and put it on. I had 18-20V spikes and two VP44s, an ECM, and 3 Juice modules later... I figured out what was going on.

Oh, and my battery's are old and I don't know HOW old.

Hey guys, new here. I have a built 47RE by Source Auto in Clackamas, OR. I don't have a 4th gear lock/unlock problem, but a surging problem right when it goes into lockup. Did it with old transmission and new built one. It really started happening when I put in DAP 150hp injectors. Basically it will lock up way too early sometimes with OD off into 3rd gear and buck. It does it everytime, and even in 4th. Just wanted to make sure my alt was good.

So I guess my question is, where do you measure the VAC, at the alternator or batteries? I just have some cheapy Innova DMM. It has the same symbol that Moparman showed in his video, but has 2 options...200 or 500.

I tried measuring at batteries and alternator and even with engine off I get 25.6 VAC. Even when I unplugged the wiring harness at alternator it's the same.

Doing something wrong, or do I need to borrow someones Fluke?

- - - Updated - - -

Think it might be my meter (Innova 3310). I just tested my laptop charger that's supposed to be 19.5v, showed 42v. Just for fun tried AAA 1.5v battery, showed 1.32V DC and almost 2.8v AC?

Well I unscrwed the 140A alt fuse, and it made no difference so I don't think this is my problem.

Well I unscrwed the 140A alt fuse, and it made no difference so I don't think this is my problem.

Did you get a good meter and see what the reading is?

Not yet, maybe I can do it tomorrow. Really curious to see what it's at.

Here are my 2 most up to date videos...

Just tested my VAC with my Dad's Fluke 73. Was reading about .006v to .010v AC with about 14.24v DC at idle so seem to be good shape there.

PASSING Grade! :thumbup2:Also come to my attention that cheap DVM's tend to report this 30 volt level. Where a high quality Fluke or similar with report proper voltage.

PASSING Grade!

Also come to my attention that cheap DVM's tend to report this 30 volt level. Where a high quality Fluke or similar with report proper voltage.

Good point! I will try it with my Greenlee CM-1350.

Standby....

- - - Updated - - -

Good point! I will try it with my Greenlee CM-1350.

Standby....

I checked it with my Greenlee and it is at .3 VAC; that makes me feel better. Also 14.4 VDC.